All the recent talk of “fake news” has an overlooked angle here in New York — where fake news has long plagued the horse-carriage industry. Who’s responsible for elevating fabrications into fact? Mayor de Blasio.

De Blasio won office partly on a bizarre promise: He’d ban Central Park’s horse carriages. In making this pledge, he gained campaign contributions. Prosecutors are looking into whether this was bribery.

The mayor repeatedly tried to ban the carriages but lost in the City Council. At one hearing, the Mayor’s Office couldn’t give evidence that horses were mistreated or in danger. Yet in the process, the mayor did a dangerous thing: repeat bald untruths as fact.

The mayor has written that horse carriages are banned in Paris and London. They’re not. “I think it’s horrible what happens to the horses,” the mayor said, referring to long-debunked reports.

Now, animal-rights activists are seizing on these untruths as they again go after horse-carriage drivers, even more aggressively.

Since fall, activists have congregated around the horse trade’s Central Park South “hack line” — where drivers pick up passengers. What protesters lack in numbers they make up for in bullying.

But when she learned, through a former driver, about the trade’s plight, she investigated.

In one of Bachom’s videos, an activist walks up to a driver and hits him, hard (he was charged with assault).

In another, a young woman targets children. Speaking to a woman and four little girls in a carriage, she says, “The horse is very sad. They drop dead in the streets. They crash into cars. The children have no seat belts. Look at how dangerous this is.”

A protester tells a different passenger: “You realize you are abusing animals.” The customer tells the protester: “Please go away. This is my private space.”

Edita Birnkrant, of the Empty the Carriages group, denies aggressive behavior. “We’re merely talking to people,” she says. “We’re ­offering a flier to people” and “enabling the tourists to make a more informed choice.”

But it’s one thing to protest, hand out leaflets or shout. It’s another to chase a carriage down a Central Park road, screaming at specific customers to stop abusing animals.

Even in public, a person has a legal right to be left alone once she tells another person to leave her alone. This is a right the mayor is not enforcing, leaving tourists to be targeted and bullied.

Activists also encourage customers to take a ride in a large electric car. Cars are mostly banned in Central Park, so the car must take people around Midtown’s congested streets. Just what Midtown needs — another car.

Craig Sheldon, a lawyer, says he “was never interested at all” in horse carriages “before de Blasio got elected. I was a little bit offended by this idea that he was going to put the workers out of jobs.” Like ­Bachom, he decided to investigate, visiting the stables as well as the hack protests.

Sheldon sees a distinction: Ever since the protesters lost their bid to outlaw the ­industry, he notes, the protests have purposely tried “to keep the drivers from conducting their lawful business.” Sheldon started his own group where people hold up signs thanking horse-carriage customers for their support.

Still, customers see chaos and turn away.

“It’s hard to quantify” how many customers her group has deterred, Birnkrant says. “I would say quite a few, many.” Empty the Carriages is stepping up its activity for the holidays. “This is sort of the busiest season.”

A horse-carriage company just filed a lawsuit to ask a judge to enforce a 15-foot buffer to prevent harassment.

Last week, de Blasio lectured us: “You can’t have a candidate for president single out groups of Americans negatively and not have some ramification,” he said about hate crimes. True, but the mayor himself painted people engaged in a heavily regulated, scrutinized business as animal abusers. People who believe this fake news are acting on it — and giving small children who visit New York a bad memory, not a good one.

Nicole Gelinas is a contributing editor to the Manhattan Institute’s City Journal.